A superconducting wire has an electric resistance converging close to zero at a certain temperature and thus has high power transfer capability even at a low voltage.
For a superconducting cable having the superconducting wire, a cooling method performed using a refrigerant such as nitrogen to form and maintain an extremely low temperature environment and/or an insulation method of forming a vacuum layer is employed.
Conventionally, tension or torsion may be continuously applied when superconducting wires for a superconducting cable are coiled around a drum or the like while being spirally wound around an outer surface of a former or the like to manufacture a superconducting cable or when the superconducting cable is bent in a cable installation area. Such stress may cause the superconducting wires having a thickness of only about 0.1 mm to be broken. In particular, since the cost of superconducting wires occupies a largest percentage of a total superconducting cable cost, the durability or physical reliability of the superconducting wires is required.
In addition, the superconducting wires should not be damaged or deformed when physical stress such as a tensile force or torsion is applied thereto, and stable electrical properties thereof should be guaranteed.